Human Anatomy and Physiology Answers

Which action leads to the closure of the left atrioventricular valve?

a. Contraction of the right atrium

b. Contraction of the right ventricle

c. Contraction of the left ventricle

d. Relaxation of the right atrium

e. Relaxation of the left ventricle

Which of the following would cause an increase in cardiac output?

a. an decrease in stroke volume

b. an increase in afterload

c. an increase in preload

d. a decrease in heart rate

e. an addition of a negative chronotropic agent

An increase in contractility would cause:

a. a decrease in stroke volume

b. a decrease in end diastolic volume

c. a decrease in end systolic volume

d. an increase in end systolic volume

e. none of the above

In autorythmic SA nodal cells, the pacemaker potential is caused by the opening of "fast" voltage-gated K+ channels.

True or False

Which circuit of the cardiovascular system is responsible for sending blood to the kidneys, stomach, and pelvic organs?

a. Pulmonary circuit

b. Somatic circuit

c. Autonomic circuit

d. Systemic circuit

e. Vagal circuit

Which of the following statements concerning ventricles is not true?

a. The right and left ventricles pump different volumes of blood

b. The right and left ventricles pump blood at different pressures

c. The right and left ventricles both contain papillary muscles

d. The right and left ventricles do not contain pectinate muscles

e. All of the above are true

The opening and closing of the heart valves is caused by:

a. action potentials acting on the valve cusps

b. contraction of smooth muscle cells at the base of the valves

c. contraction and relaxation of papillary muscles

d. pressure changes during the cardiac cycle

e. magic elves and pixies

Which of these statements concerning cardiac muscle is not true?

a. Cardiac muscle behaves as a single motor unit (all fibers contract at about the same time)

b. Cardiac muscle has a relatively short refractory period

c. Cardiac muscle is involuntary

d. Some cardiac muscle fibers can spontaneously depolarize

e. All of the above are true

Upon activation, platelets release:

a. histamine and heparin

b. serotonin and thromboxane A2

c. epinephrine and norepinephrine

d. prostacyclin and angiotensin II

e. aldosterone and melatonin

The main function of leukocytes is to:

a. carry oxygen through the body

b. carry carbon dioxide through the body

c. form blood clots

d. produce antigens

e. none of the above